President Obama heads to Europe this week for talks on nuclear security and international economics.

But topic number one at the Nuclear Security Summit at The Hague, plus a meeting of G-7 leaders – it used to be the G-8 until Russia became persona non grata – will be the situation in Crimea, where Russian troops have overrun Ukrainian military bases following annexation of that region.

“The Ukrainian government is trying to use all the peaceful means, diplomatic means to stop the Russians,” Mr. Deshchytsia. “But people are also ready to defend their homeland.”

Sabers aren’t exactly rattling in the US, but the push to provide Ukrainian defense forces with military gear is growing.

Appearing on CBS's "Face the Nation," Senators Dick Durbin (D) and Kelly Ayotte (R) said the US should send communications gear and other equipment to Ukraine – but not weapons, although Sen. Durbin said he would not rule out small arms. Durbin in just back from Ukraine, and Sen. Ayotte is leading a congressional delegation there now.

“I don't see any boots on the ground right now, nor are they asking for that," Ayotte said. "I think that what we can do though is strengthen NATO.'s presence, particularly in the countries surrounding Ukraine, and also provide assistance to the Ukrainian military." She also suggests a US Navy presence in the Black Sea.

“But most importantly, we need to send a message to Vladimir Putin through stronger sanctions,” she said. “We need him to understand that the sanctions that we put in place can have a significant impact on his economy, that we need to deter further action from him. And understand who he is: A former K.G.B. colonel. He's a bully. And bullies only understand when we punch them in the nose, but we need to do that economically. That is our strongest move at this point.”

Others agree that Russia’s takeover of Crimea, surprising as it was to many – although perhaps not in retrospect, given recent history in Georgia – demands a new view of the Russian president and his intentions for other former Soviet republics and for Russians living there.

“He goes to bed at night thinking of Peter the Great and he wakes up thinking of Stalin,” House Intelligence Committee Chairman Mike Rogers (R) said on NBC’s “Meet the Press.”

“We need to understand who he is and what he wants," Rep. Rogers said. "It may not fit with what we believe of the 21st century.”

Like Durbin and Ayotte, Rogers advises sending military aid to Ukraine.

“We're not talking about even complicated weapon systems,” he said. “We're talking about small arms so they can protect themselves. Maybe medical supplies, radio equipment, things that they can use to protect themselves, defensive-posture weapon systems. In conjunction with sanctions, now you've got something that says, ‘Mr. Putin, we're done with you expanding into other countries.’”

Moving beyond economic sanction imposed on Russian officials, oligarchs, and institutions to military equipment and training for Ukraine may or may not happen as a result of Obama’s meetings with his European counterparts this week.

“What we’re seeing every day is Russia getting more and more isolated and its economy taking a bigger hit,” White House Deputy National Security Adviser Tony Blinken said Sunday on CNN’s “State of the Union.”

In any case, Obama’s trip to Europe could be pivotal, National Security Advisor Susan Rice said at a White House briefing Friday.

“If there is a common theme to this trip, it’s the fundamental strength and the importance of our alliances,” Ms. Rice said. “We are investing in our traditional alliances and building strong and flexible coalitions.”

Asked if the crisis in Ukraine necessitated a “fundamental reassessment” of relations with Russia, she had a one-word answer: “Yes.”

"I think [Putin] is calculating how much he can get away with, just as Adolf Hitler calculated how much he could get away with in the 1930s," Sen. John McCain (R) told the BBC.